Norway Rats: Information, Photos and Facts

Also called street or sewer rats, Norway rats are one of the most common invasive rodent species. These rambunctious rodents damage property and spread disease. If you’ve seen even just one Norway rat in your home, you could easily have a larger infestation lurking. Here’s everything you need to know about these tiny troublemakers, including how to exterminate them.

Facts, Identification, and Control

Before learning how to defeat these rats, you’ll first want to learn a bit about their biology and behavior.

Latin Name

Rattus norvegicus

Appearance

Norway rats have a rather generic appearance; they’re likely what you think of when you think “rat.” They’re between seven to nine inches long with a six to eight tail. Their tail is shorter than the length of their body and hair.
Also, they’re usually brown. Their fur is coarse and often oily. Their underside is usually gray, off-white, or, on occasion, yellow.

Norway rats look a lot like roof rats. Here’s a brief rundown of their differences:

• Norway rats are almost always light brown; roof rats are dark brown or black.
•  Norway rats have shorter tails than roof rats.
•  Norway rats have longer, bulkier bodies
•  Norway rats don’t climb or swim. (Roof rats do.)

Check out the Norway rat pictures below for more information, including an approximation of Norway rat size.

Facts about Norway Rats

Where Do They Live?

Norway rats like basements, building foundations, crawl spaces, and sewer systems. They also live outdoors, usually near dwellings, in woodpiles, fields, and around trash. They create fairly elaborate burrows in dirt or debris. Each burrow has a main entrance and an emergency exit.

What Do They Eat?

Norway rats don’t have discerning palettes. They have what’s called “foraging plasticity,” meaning they’ll eat a wide range of whatever’s around. However, they prefer variety, so they’ll often seek dumpsters and trash.

They’ll eat grains, nuts, meat, and fish. Although they’ll eat fruits and vegetables, neither are their first choice. However, roof rats tend to prefer fruits and veggies.

How Did I Get Norway Rats?

Generally, rats don’t venture beyond 150 feet of their burrows. If you see one of these rats in your home, it’s not just passing through. Instead, it’s living nearby – and it only lives near a steady food source.

They enter homes when food and water sources outside are scarce, usually during fall and winter. If you see rats inside, it’s because they’ve found an entryway such as a hole or gap.

Also, they’ve identified a food source nearby, such as unprotected pantries or garbage cans. Food outside the house encourages rats to stick around. Sooner or later, they’ll likely make their way inside.

How Serious Are Norway Rats?

Because rats tend to stay out of sight, it’s hard to know what they’re up to in your home. Unfortunately, rats can cause lots of damage in a short time. Here are the four biggest problems:

Structure and Property Damage

Norway rats have an almost supernatural ability to chew through materials. They can tear through wood, plastic, metal, and more. Left to their own devices, they’ll cause big-time structural and property damage in their search for meals.

Spread Disease and Illness

Wild rats aren’t clean. The Center for Disease Control lists a variety of diseases caused both directly and indirectly by rats. Norway rat diseases include:

• Jaundice
• Rat-bite fever
• Salmonellosis
• Hantavirus
• Plague

Ruin Food

Rats have a constant drive to find food and the chewing power to reach it just about anywhere. Even if rats only eat a small amount of a food item, you’ll have to throw out all of it. Plus, you should toss any other items the rat potentially walked over.

Create Stress and Anxiety

Rats are no fun. Although they’ll try to hide from you, you’ll still likely catch glimpses of them and hear them running around. Resting and relaxing is difficult when you have uninvited, four-legged guests.

What Can I Do About Norway Rats?

If rats have made their home in yours, it’s easy to feel overwhelmed and outnumbered. Every piece of food or furniture feels suspect. Have rats been running over your belongings? Your entire house can feel contaminated.

Fortunately, rats in your home can be exterminated and forced out. Also, a few simple techniques can effectively prevent them from returning. First, you want to assess the situation and determine where the rats likely live. Before diving into control tips, let’s cover the signs and symptoms of infestation.

Signs of a Norway Rat Infestation

Rats generally avoid people. If you do see one out in the open, the infestation is likely pretty plentiful. Rats usually only appear when their preferred spaces are full.

Check for indirect signs. Rat dropping is the most obvious. Norway rat droppings are brown, capsule-shaped, and have blunt ends. (Roof rat droppings have pointed ends.)

Rats have oily bodies. They leave behind dirty, greasy marks against walls and baseboards. Also, watch for footprints (and a thin “tail print”).

Also, rats chew on anything and everything. Watch for bite marks on walls, flooring, and furniture. New bite marks have rough edges; older bites are smooth and greasy.

Finally, watch for missing food. While it’s easy to notice a chewed-up cereal box, only rat meals are harder to detect. For example, rats love pet food. If you keep a bag of dog chow in your garage, rats can feast for a while before you might notice.

Norway Rat Prevention and Control Tips

#1 Store Wood Away from the House

Norwegian rats like to live in piles of wood. Keep your firewood away from your house. Otherwise, they’ll likely expand their nests into your home. Also, trim plants and trees near your house.

#2 – Barricade Points of Entry

Block any holes leading into your home. Common points of entry include damaged screens, areas around pipes, loose roof shingles, and other areas of disrepair.

Replace any loose boards. If you have pipes or ventilation points which you can’t block, attach steel screens. They’ll allow for air and water flow while also preventing rats from entering.

#3 – Seal Up All Food and Trash

Keep dry goods in sealed plastic containers. Don’t leave food out overnight or in the sink. Also, confine eating to one room to discourage rats from exploring.

Seal all outside garbage cans. Trash kept outside draws rats big-time. You want tight lids on every can to avoid spreading delicious scents into the wild. Also, keep cans clean and free from debris.

#4 – Use Rat Traps

Traps are usually the best removal method. Both human and kill traps are available. Set traps along travel paths. Use dropping locations as a guide.

Norway rats run against walls frequently. Place traps parallel to the baseboards. Set two traps back-to-back to catch rats running in either direction.

Norway Rats Professional Pest Control

Catching a single rat is usually simple. However, Norway rats are rarely alone. They build burrows next to one another. So, if you catch one rat, many more are likely still around.

A pest control professional is the best option for eliminating rats. Only a licensed exterminator can carefully assess your environment to determine where the rats are entering and how to keep them out.

Also, a pest pro will know what type of traps, bait, and other methods to use. Not all removable methods are equal. For example, a professional knows how to kill rats without trapping their bodies inside walls and inaccessible areas.

All rat infestations are unique. The specific layout of your home determines the most effective removal methods. A professional understands how to create a custom plan based on your needs.

Benefits of Hiring a Professional Rat Exterminator:

•  Removes rats quickly and thoroughly
• Allows for the responsible, safe removal of dead rats
•  Protects pets and family members from accidental exposure to poison
•  Creates a custom plan to barricade house from future infestations

More information on Norway rats:

• Norway Rat information from the Smithsonian Zoo
• Norway Rats by the Illinois Department of Public Health
• Guide to Norway Rats by the Alameda County CA Dept of Environmental Health
• Norway Rat .pdf guide by the U.S. Department of Agriculture

Norway Rats FAQ

Where are Norway Rats Found?

Norway rats live in almost every state, especially in wooded areas.

Are Norway Rats Dangerous?

Norway rats are unlikely to bite you or even want to engage with you. However, they can carry a wide range of diseases. Rats in your home can make you sick even without direct contact.

Norway Rat Guide Final Thoughts

By the time you see a rat in your home, you’re likely dealing with a major infestation. When rats find comfortable living quarters and a steady source of food, they stick around for a long time.

If rats have infested, it’s only natural to feel anxiety and even anger. Fortunately, removing these unwanted invaders is easier than you may think. Seal off entry points, close up any open food, and eliminate any nesting locations.

Also, consider hiring a pest professional. They can help remove rats quicker and more thoroughly than what you can accomplish yourself.

Don’t share your living space with rats! Follow the tips above to keep your home free from these furry freeloaders.